A theoretical study of a vertical parallel junction under constant multispectral light has been made.
By using a new approach of the carrier generation rate we determine the recombination and electrical
parameters. The photocurrent density JPH is presented as a calibrated function, diffusion length dependent. It
intercepts with the experimental short circuit current density JSC, at the minority carriers diffusion length L
value. The photo voltage as a calibrated function of surface recombination velocity intercepts the experimental
open circuit voltage at the junction intrinsic recombination velocity. The shunt and series resistances are
presented respectively as a calibrated function of the surface recombination velocity and it intercepts with the
value of junction recombination velocity in short circuit SFSC or in open circuit SFOC at the experimental shunt
and series resistances value.